Attention deficit hyperactivity disorder (ADHD), is a neurodevelopmental/ neurobehavioral disorder which affects 4-6% of the world's population. Symptoms are usually identified during childhood and are characterized by a pattern of inattention, high distractibility, impulsivity, and/or hyperactivity. In contrast to the thinking in earlier years, ADHD is a persistent or chronic condition for which no medical cure is currently available. It is estimated that between 60 and 80% of children diagnosed with ADHD exhibit symptoms well into adulthood. Accurate assessment of this factor is made difficult because untreated children do make adaptations to deal with their impairment which seems to lessen the severity of symptoms but masks the struggle these individuals have to function at sometimes marginal levels. There is a clear genetic contribution to the disorder although it is believed that 15 to 25% of cases may be caused from trauma or toxic exposure.
The National Institutes of Health in the United States (and throughout the world) describe ADHD as a disorder which impairs functioning and produces many adverse life outcomes. Certain social critics, religious groups, and an assortment of radio talkshow hosts suggest that ADHD is a controversial disorder. However, this opinion is well outside of the majority viewpoints among scientists who have researched the neurobehavioral and neurobiological manifestations of the disorder.
Magnetic resonance diagnostic procedures have recently documented anatomical delays in brain development of ADHD patients. The delays are primarily in the prefrontal cortex and are believed to be as much as three to five years when compared to non-ADHD peers. These studies, conducted at the National Institutes of Health and National Institute of Mental Health suggest a delay in the physical development of certain neuroanatomical structures of at least three years in the brains of over 200 ADHD patients beginning in elementary school. Findings suggest that the delay is most prominent in the frontal cortex, an area believed responsible for the ability to sustain attention, plan, inhibit inappropriate actions or thoughts, and provide for immediate recall (the basic building block for learning).
As a consequence of these studies, ADHD is classified as a neurological disorder rather than a purely behavioral disorder and is generally treated as a neurobehavioral or neurodevelopmental disorder.
The majority of scientific opinion regarding the expression of ADHD is that it is a chronic and persistent disorder for which there are some effective treatments but no cures. There is no single method for diagnosing ADHD, but certainly the reliance on behavioral rating instruments alone is inadequate in that a multitude of psychological and other emotional traumata and conflicts produce symptoms that present like ADHD. According to the Physician's Desk Reference, special diagnostic considerations apply to ADHD. The diagnoses requires "the use not only of medical but of special psychological, educational, and social resources. The diagnosis must be based upon a complete history and evaluation of the child and not solely on the presence of the required number of DSM-IV characteristics."